Husband replaced the fuel filters, purged the system, but when I turn the key on the starter engages but stays engaged and truck does not start. Help please

  • Welcome to Motor Vehicle Maintenance & Repair! Did it run properly before the fuel filters? Commented Sep 12, 2023 at 23:02
  • It sure did. That’s why we don’t understand
    – Barb
    Commented Sep 13, 2023 at 0:07

1 Answer 1


I think you're saying that the starter will crank for as long as you hold the key in the START position, but the truck will not start. (If the engine has started in the hours since you posted your question but it is running rough, the same procedure below will fix it.)

When the fuel filter is changed on a diesel engine, it's important to fill the new filter as full as possible with fuel before installing the new filter so that the fuel system does not get air in it. You have air in your fuel system. This is why it won't start.

You said the fuel system was purged, but I think the purge was not effective. The following procedure will fix it:

  1. Find all 8 fuel injectors and loosen the fuel fitting on each of them about 1/4 turn.

  2. Wrap all 8 fuel fittings on the injectors with clean rags to catch the fuel that will leak.

  3. Engage the starter and crank the engine for 10 seconds. (The engine will not start.) Wait one minute, then crank for 10 more seconds.

  4. Now remove the fuel-soaked rags and tighten the fuel fittings at each injector. If you created any puddles of fuel on the engine, wipe them up. Note: if the rags are not wet with fuel, either the fuel fittings were not loose enough or there is still more air in the injector pump. Do not proceed with step 5 until the rags are wet with fuel.

  5. Now start the engine. It should start but it might stumble due to a small amount of air remaining in the fuel lines. If it is stumbling or running rough, run the engine at higher speed (2000 - 2500 RPM) for about one minute.

The engine should be fine now. Please let us know how it worked out by making a comment below this answer.

  • Thanks so very much for the advice, we did in fact get it running yesterday. Again thanks!
    – Barb
    Commented Sep 15, 2023 at 16:02

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .